Like other modes of transportation, flying is dangerous. Unlike other modes of transportation, aircraft are capable of traveling at relatively high speed at great altitude. Thus, unlike other modes of transportation, extensive training is required before one may safely pilot an aircraft. A large portion of a pilot's training is the safe navigation of the aircraft from one location to another. After all, to transport people or things requires the ability to ascertain the current location of the aircraft with respect to the destination.
The navigation process begins prior to departure. The pilot determines the most appropriate flight path from the current location, taking into account factors such as weight of the aircraft, fuel required, weather conditions between the departure and arrival location. During the flight, the pilot records the progress of the flight against the flight plan. This exercise helps identify potential problems prior to those problems becoming emergencies. The pilot may use two basic methods for navigating an aircraft.
The first basic navigation method is according to VFR, or Visual Flight Rules. The second is IFR, or Instrument Flight Rules. While flying according to the IFR, many instruments on a flight deck of an aircraft are used. One of the primary navigational aids that the pilot uses to determine whether the aircraft is on the planned flight path is a HSI, or Horizontal Situation Indicator.
The HSI provides a visualization of the position of the aircraft with respect to a multitude of navigational sources that can be displayed on an electronic or mechanical HSI. For years the VOR has been the primary source of aircraft navigation using an HSI. The VOR (VHF Omnidirectional Radio Range) radial signal broadcast by a VOR station, which are known in the art. The HSI also has a compass, or simulated electronic compass, integrated into it that displays the direction that the plane is headed with regard to the earth's magnetic field. For one skilled in the art it is understood that any reference to compass herein also includes simulated compasses such would appear on an electronic display or projected image. Further, one skilled in the art will understand that a full compass need not be displayed at all times. In fact, only a portion of the compass may be displayed at any one time in what is referred to as “arc mode.” The heading of the aircraft is determined with the compass. In the past, to successfully navigate through the “airways in the sky,” the pilot tunes into desired frequencies broadcast from a VOR station. Each VOR station has a unique frequency that it broadcasts two 30 Hz reference signals to encode direction to and from the VOR station along VOR radials. By tuning into the VOR station frequency, for instance located at an airport, and decoding the phase difference between the two 30 Hz signals a representation of any one of the radials may be displayed on the HSI. Thus, the HSI provides visual and numerical information of where the aircraft is relative to the VOR radial that the pilot desires to use.
During flight, the pilot, in part, monitors the HSI to verify the location of the aircraft against the flight plan. Also during flight, the desired heading and the VOR radials may be changed or adjusted multiple times, depending on the length of the trip, to guide the aircraft from one VOR radial signal to a next VOR radial signal along the scheduled flight path. The HSI generally has two controls on its face. A heading select knob controls the position of a heading select bug which indicates the desired heading of the aircraft. A course select knob is used to select the VOR radial.
With advancement in technology aircraft are using many different sources for navigation that are displayed on the HSI. In the art it is commonly known that an HSI can be used to navigate with various sources of navigational equipment including but not limited to the following systems which will be referred to throughout as simply “navigational aid”: the VOR as previously discussed: LOC (localizer); LDA (Localizer Type Directional Aid); TACAN (Tactical Air Navigation); VORTAC (VHF Omni-Directional Tactical Air Navigation); GPS (Global Positioning System); INS (Inertial Navigation System); FMS (Flight Management System); MLS (Microwave Landing System); LORAN (Long Range Navigation-C); IRU (Internal Reference Units); WAAS (Wide Augmentation System); GLS (Global Landing System); and TLS (Transponder Landing System), all terms known to one skilled in the art and as described in the Federal Aviation Administration (FAA) Aeronautical Information Manual (AIM). Some of these navigational aids are transmitted from ground based stations such as conventional VOR stations, others from satellites, and others are internal to the aircraft such as gyro based systems. To navigate using these navigational aids the pilot will adjust the OBS (Omni-Bearing Selector) to the desired radial or for the desired course. Some of the afore mentioned navigational sources will automatically set the OBS for the desired course, however some just indicate a suggested course that the pilot must then set. All of these navigational sources will be displayed on the CDI (Course Deviation Indicator) on the HSI. These sources will automatically set the CDI on the HSI to a predetermined course that the pilot has selected and or entered, but some may require the pilot to do this manually. The CDI will show the course on the HSI in respect to the navigational radial or course to be flown. This radial will be a magnetic heading as displayed on the HSI.
Since heading select knob and the course select knob are generally located on a front face of the HSI, or in some other remote location, the pilot must release one hand from the yoke or a throttle, power levers, or the collective in helicopter and grasp and rotate the knob to make the adjustment. Releasing the yoke creates safety issues in at least two situations. The first situation occurs when flying into or out of high density traffic areas. In high density traffic areas, where there are many other aircraft in the vicinity, quickly identifying potential collision courses and taking immediate evasive action may be the difference between a near miss and a collision. The second situation occurs in bad weather where the pilot may have difficulty adjusting the aircraft's attitude in response to external forces. Again, releasing the hand from the yoke to make an adjustment to the HSI creates safety problems and may cause spatial disorientation. Both situations are aggravated by darkness when flying according to IFR. To make matters worse, if there is only a single pilot, making a landing approach in bad weather or in darkness is a safety hazard not only for the pilot and passengers, but for the people on the ground. In all of these situations maximizing control of the aircraft by keeping one hand on a yoke and the other on the throttle(s) or power lever(s), or cyclic and collective in the case of helicopters, is preferable. However, it is often necessary to adjust the heading and select a new course on the HSI while flying under these conditions. So, the pilot will often risk spatial disorientation or losing control of the aircraft by flying with one hand off of either control to make a heading or a course adjustment.
Fortunately, many aircraft have two seats, the captain's seat, and the first officer's or right seat. Each seat has its own set of flight controls complimented by similar gages. The purpose of multiple seats with multiple flight controls is improve safety by providing at least one redundant set of controls and instruments in case of the failure of the primary set. However, the captain's controls generally do not interact with the first officer's controls, meaning that little, if any, information is exchanged between the two. Therefore, in the severe weather and high density traffic situations discussed above, the pilot sitting in the captain's seat is in sole control of the aircraft, even if another pilot is sitting in the first officer's seat. In other words, the first officer is unable to help fly the aircraft even if the captain made a request for help.
What has been missing in the art has been a system by which the pilot may maintain a firm grip on the yoke, however, a system which allows the pilot to adjust the heading and the course of the aircraft while at the same time gripping the flight controls. In addition, the prior art is missing a system that allows one pilot to transfer part of the navigation responsibilities to the other pilot. Furthermore, the art has been missing a system where the pilot may quickly assess which set of instruments has control of the aircraft.